﻿using System;
using System.Linq;
using System.Collections.Generic;
using System.Text;

using System.Runtime.InteropServices;
using System.Drawing;
using Microsoft.WindowsCE.Forms;

namespace LavajatoMobile
{

    /// <summary>
    /// Handles showing and hiding of Soft Input Panel (SIP).  Better to use these
    /// methods than having an InputControl on a form.  InputControls behave oddly
    /// if you have multiple forms open.
    /// </summary>
    public class SIPHandler
    {
        public static void ShowSIP()
        {
            SipShowIM(1);
        }

        public static void ShowSIPNumeric()
        {
            SipShowIM(1);
            SetKeyboardToNumeric();
        }

        public static void ShowSIPRegular()
        {
            SipShowIM(1);
            SetKeyboardToRegular();
        }

        public static void HideSIP()
        {
            SipShowIM(0);
        }

        private static void SetKeyboardToRegular()
        {
            // Find the SIP window
            IntPtr hWnd = FindWindow("SipWndClass", null);
            // Go one level below as the actual SIP window is a child
            hWnd = GetWindow(hWnd, GW_CHILD);
            // Obtain its context and get a color sample
            // The premise here is that the numeric mode is controlled by a virtual button in the top left corner
            // Whenever the numeric mode is active, the button background will be of COLOR_WINDOW_TEXT
            IntPtr hDC = GetDC(hWnd);
            int pixel = GetPixel(hDC, 2, 2);
            // Notice that we cannot simply compare the color to the system color as the system color is 24 bit (or palette)
            // and the real color is dithered to 15-16 bits for most devices, so white (0xff, 0xff, 0xff) becomes
            // almost white (oxf8, 0xfc, 0xf8)

            // ken's hack:  here we only want to simulate the click if the keyboard is in numeric mode, in 
            // which case the back color will be WindowText
            //int clrText = (SystemColors.Window.R) | (SystemColors.Window.G << 8) | (SystemColors.Window.B << 16);
            int clrText = (SystemColors.WindowText.R) | (SystemColors.WindowText.G << 8) | (SystemColors.WindowText.B << 16);

            SetPixel(hDC, 2, 2, clrText);
            int pixelNew = GetPixel(hDC, 2, 2);
            // Restore the original pixel
            SetPixel(hDC, 2, 2, pixel);

            if (pixel == pixelNew)
            {
                // Simulate stylus click
                Message msg = Message.Create(hWnd, WM_LBUTTONDOWN, new IntPtr(1), new IntPtr(0x00090009));
                MessageWindow.SendMessage(ref msg);
                msg = Message.Create(hWnd, WM_LBUTTONUP, new IntPtr(0), new IntPtr(0x00090009));
                MessageWindow.SendMessage(ref msg);
            }
            // Free resources
            ReleaseDC(hWnd, hDC);
        }

        private static void SetKeyboardToNumeric()
        {
            // Find the SIP window
            IntPtr hWnd = FindWindow("SipWndClass", null);
            // Go one level below as the actual SIP window is a child
            hWnd = GetWindow(hWnd, GW_CHILD);
            // Obtain its context and get a color sample
            // The premise here is that the numeric mode is controlled by a virtual button in the top left corner
            // Whenever the numeric mode is active, the button background will be of COLOR_WINDOW_TEXT
            IntPtr hDC = GetDC(hWnd);
            int pixel = GetPixel(hDC, 2, 2);
            // Notice that we cannot simply compare the color to the system color as the system color is 24 bit (or palette)
            // and the real color is dithered to 15-16 bits for most devices, so white (0xff, 0xff, 0xff) becomes
            // almost white (oxf8, 0xfc, 0xf8)
            int clrText = (SystemColors.Window.R) | (SystemColors.Window.G << 8) | (SystemColors.Window.B << 16);
            SetPixel(hDC, 2, 2, clrText);
            int pixelNew = GetPixel(hDC, 2, 2);
            // Restore the original pixel
            SetPixel(hDC, 2, 2, pixel);

            if (pixel == pixelNew)
            {
                // Simulate stylus click
                Message msg = Message.Create(hWnd, WM_LBUTTONDOWN, new IntPtr(1), new IntPtr(0x00090009));
                MessageWindow.SendMessage(ref msg);
                msg = Message.Create(hWnd, WM_LBUTTONUP, new IntPtr(0), new IntPtr(0x00090009));
                MessageWindow.SendMessage(ref msg);
            }
            // Free resources
            ReleaseDC(hWnd, hDC);
        }

        [DllImport("coredll.dll")]
        private extern static bool SipShowIM(int dwFlag);

        [DllImport("coredll.dll")]
        private extern static IntPtr FindWindow(string wndClass, string caption);

        [DllImport("coredll.dll")]
        private extern static IntPtr GetWindow(IntPtr hWnd, int nType);

        [DllImport("coredll.dll")]
        private extern static int GetPixel(IntPtr hdc, int nXPos, int nYPos);

        [DllImport("coredll.dll")]
        private extern static void SetPixel(IntPtr hdc, int nXPos, int nYPos, int clr);

        [DllImport("coredll.dll")]
        private extern static IntPtr GetDC(IntPtr hWnd);

        [DllImport("coredll.dll")]
        private extern static void ReleaseDC(IntPtr hWnd, IntPtr hDC);

        [DllImport("coredll.dll")]
        private static extern bool SipSetCurrentIM(byte[] clsid);

        const int WM_LBUTTONDOWN = 0x0201;
        const int WM_LBUTTONUP = 0x0202;
        const int GW_CHILD = 5;

    }
}

